Brush strip construction



Feb. 3, 1959 B. E. NELSON 2,871,496

BRUSH STRIP CONSTRUCTION Filed Aug. 26. 19 54 D D b A T7078 NE V5 itel States "tem BRUSH STRIP CoNsTRUCTIoN Brooks E. Nelson, Chagrin Falls, Ohio, assignor to The Osborn Manufacturing Company, Cleveland, Ohio, a Corporation of Ohio Application August 26, 1954, Serial No. 452,319

12 Claims. (Cl.15-182) form back within which brush bristle material is secured by means of an elongated retaining element Such as a Wire has become an important article of Commerce and is produced in large quantties. While much brush strip is employed in the manufacture of hand brushes and dusters, a principal use is in the manufacture of power driven rotary brushes. Such brus'hes may be composed of a series of annular sections formed by individual turns of brush strip with the brush material extending generally radially outwardly therefrom or a long length of brush Strip may be wound upon a mandrel to circularize the same and produce a cylindrical or roller brush. Brushes of this type are becoming of increasing importance in industry.

Preferred forms of brush strip are shown and described in Peterson Patent 2,303,386 and in my prior Patent 2,609,242. Various other forms of brush strip are also known in 'the art characterized by an elongated back Within which the brush material is secured by a Wire Ictaining element extendng longitudinally therein. Brush strip of the type indicated is produced in continuous lengths on automatic machnes and is then wound on an appropriate mandrel or arbor as produced to circularize the Same. Lengths of such circularized brush strip Comprising one or more turns are thereupon Severed from the resultant helix to produce the desired brush element.

'When Severed in the form of Straight lengths, a small amount of brush material may be shed at the Severed ends but When Wire retaining teeth of the type disclosed in Patent 2,303,386 are provided, such shedding will be minimized: The Severed ends of the brush strip back may also be pinched to close the Channel.

When the brush strip is circularized, it Will immediately be apparent that the Wire retaining element iS-required to describe a Circle of greater diameter than the inner periphery of the brush back although when the brush strip is Straight, the length of the Wire and back Will obviously be the same. Accordingly, the Wire is greatly tensioned by the circularization operation, tending further to compact the 'brush material retained beneath it.

-Then when the circularized brush strip is Severed, the

tension on the Wire is released and it contracts arbuptly to substantially its original length, permitting s'hedding of the brush material adjacent the two ends of the Circularized strip. Slippage of the Wire longitudinally of the sle strength to secure the brush bristle material against the effect of centrfugal force. Also, Such relatively soft Wire will Work-harden when it'is stretched and therefore Still tend to contract when the brush strip is Severed. Extreme tensioning of the retaining Wire during circularization has yet another undesirable efiect in that, by further compacting the brush material, it shifts radially inwardly of the brush element away from the securing teeth which overlie it. When the 'brush strip is thereafter Severed, the wire may then be relatively loose between the compacted brush bristle material in the bottom. of the channel back and the overlying teeth, permitting excessive shedding of the brush material.

It is accordingly a principal objectof my invention toprovide novel brush Strip having an elongated retaining element securing the brush material Within the brush back which will accommodate itself to the longitudinal stresses imposed When such brush Strip is circularized.

Still another object is to provide such brush strip vwhich Will not tend to shed brush material unduly when such strip is circularized and then Severed to provide annular brush elements of one or more turns. t

Other objects of the invention will appear as the description proceeds. i i

To the accomplishmentof the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the Claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the Various ways inwhich the principle of the invention may be employed.

In said annexed drawing: i

Fig. 1 is a sexni-diagrammatic View illustrating the manufacture and circularization of my new brush strip;

Fig, 2 is a transverse section taken on the line 2-2 on Fig.l;and v v i Fig. 3 S an enlarged view of the elongated brush material retaining element incorporatcd in such brushstrip.

The preferred example of'brush strip embodying the principles of my invention illustrat'ed in the drawing may be produced in a manner generally similar to that employed in the manufacture of-the brush strip disclosed and claimed in PeterSoIi'Patent 2303386. Teeth 1 are punched up adjacent the edges' ofa flat elongated Sheet metal strip 2, ordinarily steel, withsuch teeth lying in planes transverse of such'strip and-^somewhatspaced from the respective strip edges as shown. V Brush 'bristle material 3 is placed transversely of the strip and an elo'n gated Wire retaining element 4 is laid thereon along 'the longitudinal center line of the Strip. The, strip is then deformed into a channelform back 5 withthe teeth 1 extending inwardly from the channel Sides and closely overlying retaining Wire 4 as best shown in Fig. 2. The brush bristle material-3 'is thereby doubled about wire' 4 and held in place within the channel back by the'latter.

When such brush strip'is circularized as shown in Fig. 1, for example, it is readily apparent that .Wire 4 is caused to define a Circle of considerably larger'radius than the inner periphery of the brush back. The radially outer edges of the channel backs are stretched by such 'circularizatiom and wire '4 must likewise stretch *sufficiently'to accommodate the difference between 'the circumference of the Circle it describes and the 'circumference described by the. inner periphery' of the brush back v p I have found that if the retaining element 4 is madeof somewhat ductile material such: as low carbon =Steel SAE 1020 annealedwire, and such wire is also 'crimped in the manner illustrated in =Fig. 3 of'thedrawing, it will stretch permanently sufliciently to avoid .conse'quential contraction upon severin'glzof the.circularized brusl Strip a' full Curve of the crimpmay have a .27 inch frequency and an over-all amplitude of from .100 to .175 inch. The smaller the inner diameter of the circularized brush element, the greater should be the amplitude of the crimp. In the past, the greatest difficulty has been encountered When brush strip hasbeen circularized about a relatively small radius.

The channel back 5 may be formed of a variety of i materials as Well known in the art, including aluminum, Copper, brass, steel, Stainless steel, and even certain Synthetic plastic-materials. Likewise, a Wide variety of brush material may be' utilized including tampico fiber, horsehar, Wire, cord, plastic coated Wire, plastic coated cord, synthetic plastic monofilaments, and various types of fabric buff materials. The retaining element 4 may be of any suitable ductle material capable'of taking the desired crimp including 10W carbon annealed steel, aluminum, Copper, and brass. i

It Will be seen from the foregoing that I have provided novel brush strip capable of being circulariZed about a relatively Small radius to form annular rotary brush elements When Severed into desired lengths, such brush strip continuing firmly to retain the brush material therein despite the effects of csuch circularizing and Severing Operations. The circularizing operation efiects a stretching and straightening out of at least a portion of the crimp in the Wire retaining element, and such latter element is of Suflicient softness 'or ductility that When the brush strip is thereafter Severed, there is little tendency to reveIt to the previously crimped Condition. In other Words, the stretching of the retaining element is permanent Without, however, causing any very substantial cold Working of the element, undue compacting of the brush material thereunder, or the buildup of longitudinal stresses resulting in shrinkage of the Wire When Severed.

'The crimped 'Wire retaining element of my invention Should 'preferably be of round cross-section to avoid undue local concentrations of stress in the bristles secured thereby. The fiexible channel back Will ordinarily be substantially straight-sided and the Wire Will, of course,

be crimped before being secured therein. Since the crimp Will not usually be entirely reduced by the tension resulting from' circularization or like deformation of-the brush element, it is of further service in enga'ging the inWardly projecting teeth to prevent shifting in use.

\ Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features Stated in any ofv the following Claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

1. Brush strip having an elongated Sheet metal channelform back, a Wire retaning element extending separately'longitudinally Within such channel, a continuous* layer of brushmaterialretained beneath said Wire and protruding from said back, and teeth puuched in from the respective channel Sides overlying and engaging said Wire to hold the latter in'place; said Wire being smoothly continuously crimped relative to the channel Sides throughoutits. length and Sufficiently ductle substantially to maintain its Stretched Condition When elongated and suchcrimp is at least partially Straightened by imposition of longitudinal tension thereon, and the Sides of said channel back being substantially flat.

2. Brush strip: having an elongated channel back, a

separate Wire retaning element extending longitudinally Within such channel, and acontinuous layer of brush material retained beneath said Wire and protruding from said back; said Wire being smoothly continuously crimped relative to the channel Sides 'throughout its length and therefore of greater absolute length along its sinuous Course than Said back and sufficiently ductle substantially to maintain its stretched Condition When elongated and such crimp is at least partially straightened by imposition of longitudinal tension thereon.

3. A brush element including' a support portion having an elongated channel, a separate elongated retaining element extending longitudinally Within such channel, and a continuous layer of brush material retained beneath Said element and protruding from Said channel; said element being crimped relative to the sidesof such channel and therefore of greater absolute length along its sinuous Course than said back as Well as sufficiently ductle substantially to maintain its stretched Condition relative to Said back Whensuch crimp is at least partially Straightened by impositionof longitudinal tension thereon.

4. A brush' element including an elongated Straight fleXible back having a longitudinal channel therein, an elongateretaining element' extending separately longitudinally Withinsuch channel, and a layer of brush material retained beneath said element and protruding from Said channel; said element being pre-crirnped relative to Said Straight channel back and therefore of greater absolute length along its sinuous course than said back to facilitate stretching relative to Said back When said back is flexed. V

5. Brush strip having an elongated Sheet metal channelform back, a single Wire retaining element extending separately longitudinally Within such channel, a layer of brush material retained beneath Said Wire and protruding' from said back, and teeth puuched in fromthe respective channel Sides overlying and engaging Said Wire to hold the latter in place; said Wire being of annealed loW carbon SAE 1'020 steel and smoothly pre-crimped relative to the Sides of said channel back in substantially a sine Wave Curve having a frequency of approximately .27 inch and an over-all amplitude of approximately .100 to .175 inch in the case of .072 inch diameter Wire, said Wire being of greater absolute length along its sinuous course than said back and sufliciently ductle substantially to maintain its stretched Condition When such crimp is at least partially straightened by imposition of longitudinal tension thereon due 'to circularization of said brush strip, the remaining crimp in said Wire engaging such teeth and tending to prevent longitudinal shifting of said Wire.

6. In a brush'element' having a unitary circularized Sheet metalchannel back, and brush material retained in Said back and protruding radially outwardly therefrom; a smoothly crimped Wire' retaining member extending separately longitudinally Within such channel and overlying Said brush material efiective to Secure said brush material in place, such crimp being relative to the Sides of said back assisting in preventing shifting of said brush material and in accommodatng longitudinal stresses in said Wire. A

7. In a brush element having a 'circularized substantially straight-sided sheetmetal channel back, and folded brush material retained in said back' and protruding radially outwardly therefrom; a Single smoothly crimped round Wire retainingmember extendng separately longitudinally Within' Such channel overlying the fold of said brush material and effective to secure said brush material in place, Such crimp* being relative to the Sides of said channel back assisting in preventing Shifting of said brush material and in accommodating longitudinal stresses in said Wire.

8. A brush element in' accordance With Claim 7 also having teeth puuched infrom a-channel side of Said' 5 tionally engaging Such crimp to asslst in restricting Shifting of Said Wire.

9. In the method of orming a circularized brush strip element having radially outwardly extending brush material including the Step of Securing brush material in an elongated fiexible Sheet metal channel back beneath a single Wire retaining element; the preliminary step of smoothly and uniformly crimping said Wire relative to such back, and the subsequent step of tensioning said Wire during circularization of Said strip at least partially permanently to reduce Such crimp and thereby effectively elongate said Wire.

10. In the method of forming a circularized brush strip element having radially outwardly extending brush material including the Step of securing brush material in an elongated fiexible Sheet metal channel back beneath a Single Wire retaining element; the prelminary step of crimpinf Said Wire prior to insertion in Such channel, and the subsequent step of tensioning said Wire during circularization of Said strip at least partially permanently to reduce such crimp and thereby efi'ectively elongate said Wire relative to the inner periphery of such circularized back.

11. in the method of forming a brush element including the step of securing brush material in an elongated fleXible Sheet metal channel back beneath a Wire retaining element; the preliminary step of crimping said Wire, and the subsequent Step of deforming Said back longitudinally to tension Said Wire at least partially permanently to reduce such crimp and thereby efectively elongate Said Wire.

12. In a brush element having a Sheet metal channel back, teeth protruding inWardly from the channel Sides, and folded brush material retained in said back With both end portions protruding therefrom; a separate Wire brush material retaining member disposed longitudinally Within said channel beneath said teeth and overlyng said folded brush material to Secure the latter therein, Said Wire having an undulating conformation relative to the Sides of Said back adapted to engage said teeth to resist longitudinal displacement relative to said back, and also being of greater absolute length. along its Sinuous course than said back as Well as suificiently ductile to permit permanent stretching both of Such undulations and of the Wire itself When said back is subsequently circularized With said brush material extending radiab ly outwardly, thereby forcing Said Wire to take a longer path than the inner periphery of said back, but Said Wire having a high ultimate strength Safely to Secure said brush material in place in Said circularized back.

References Cited in the file of this patent UNITED STATES PATENTS 980,091 Friedley Dec. 27, 1910 1,663,584 Cleaves Mar. 27, 1928 .2.303386 Peterson Dec. 1, 1942 2,349,644 Wesemeyer May 23, 1944 2,787,0l7 Abbrecht Apr. 2, 1957 

